The Triumph of Slime, Part 2: invertebrate blob-things

So this post is on blob-kind. Jellyfish, sea cucumbers, sea slugs, salps, and so on. I’ll save salps for last, since I find them more interesting (in this case), so on to the others.

Jellyfish have been making the news recently, especially with the plague of giants afflicting Japan’s fishing industry, and there’s also concern about smaller, more lethal species that seem to be proliferating as well. Basically the warmer water seems to make life easier for adult jellyfish and might even be spurring the polyps to go into jelly-producing overdrive. This means that at the same time the Japanese fishermen are growing increasingly worried about their catch, more and more beaches and reefs around the world are becoming dangerous as the proliferation of hard-to-see, far-reaching, lethal creatures begins to crowd in on them. Of course, the warming isn’t all we’ve been doing to help the sea jellies. We’ve also been overfishing, which is lowering competition for food, and we’ve been creating dead zones. It seems that while fish, and many other creatures can’t take the extremely low oxygen content of the water in dead zones, jellyfish manage just fine. This means that if you hearken back to worst-case scenario #1 with the increase of anaerobic bacteria producing copious amounts of hydrogen sulfide, before we get to the point where the oceans are spewing out toxic gas, we would, in all likelihood, have seas filled with masses of jellyfish, many of which might find a way to hang around once the gas began leaking out onto land. I was saving this for later, but I think this is an appropriate place to point out that the nightmare of Coleridge’s Ancient Mariner may yet turn out to be a prophetic vision:

“The very deep did rot: O Christ!
That this should ever be!
Yea, slimy things did crawl with legs
Upon the slimy sea.”

We now leave the Jellyfish at the surface, and move down the water column to look at sea slugs and sea cucumbers.

Sea cucumbers are currently on a knife’s edge, of sorts. There is increasing evidence that as fish and arthropods struggle to deal with warm, acidic oceans, sea cucumbers will be able to deal just fine with the changing conditions. This could lead to a proliferation across the sea bed as occurred off of Ireland in 1996-99, but for one factor. As fisheries dwindle, humans will be looking for food, and in Asia, the art of sea-cucumber cookery has already been developed enough that while less enterprising parts of the world expect a rise in the population of these tubular tethyans, the seas around Asia and areas of the Pacific are seeing only an increase in their harvest.

Sea slugs are fascinating in their own right. They are well known (by those of us who pay attention to this sort of thing) for the trait of storing the nematocytes of jellyfish and sea anemones that they eat, and moving  them through the gut and out to their periphery to use as defensive weapons, but a fairly recent discovery has given them a new level of cool. While certain sea slugs have been known to absorb and re-use chloroplasts from algae, they need to be supplied with chlorophyll – the essential pigment for photosynthesis. It seems that one species may have stolen the genes necessary for producing the pigment, and is creating its own chemical energy. This is really cool. This ties in well with part one too, since the abundance of algae combined with the die-off of other forms of  life that might feed a sea slug would lend itself to a population boom. It’s also interesting because it was discovered at a time when corals are struggling. Coral polyps have a symbiotic relationship with algae which provides them with chemical energy, but when temperatures rise, the polyp has to eject the algae in an effort to keep things cool. If temperatures fall again, they are able to accept another back in again, but that is becoming increasingly less frequent. In their place, then, we may soon have sea slugs, leaf-like and slimy, forming slowly undulating fields of green across the sea floor.

This will be continued very soon in an update – there are more blobs to discuss!

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